Nutrition Lesson #4–Vitamins Part 1

It is the science that links foods to health and disease. It includes the ingestion, digestion, absorption, transportation and excretion of that food.

First there is food, and then there are nutrients. Food provides energy through calories. Nutrients are the substances obtained from the food we eat that are vital for growth and maintenance of a healthy body. There are 6 sources of these nutrients. They are carbohydrates, lipids, proteins, vitamins, minerals and water.

I am going to go over each of these on a different day on my website and I will always link to the back posts so those of you that are new can catch up.

Three weeks ago we talked about Carbohydrates. You can read that post here.

Let’s take a closer look at the individual vitamins, what they do for our bodies and (in some cases) what a deficiency or excess amount can do.

Vitamin A

Vitamin A has a large role in vision. It allows certain cells in your eyes to be able to quickly readjust from bright to dim lighting. It also affects color vision. Without a sufficient amount of dietary vitamin A, the cells cannot readjust quickly enough. This is a condition known as night blindness. Vitamin A is also responsible for maintaining the health of cells that line the inside and outside of your lungs, intestines, stomach, urinary tract, reproductive systems and bladder. These cells help prevent bacterial infection. Vitamin A is also required for bone growth in children. It has been reported that some children who have had a vitamin A deficiency have experienced growth retardation, but upon receiving vitamin A supplements, the children increased in height. Vitamin A may also help prevent CVD (Cardiovascular Disease) and cancer. Most forms of cancer occur in cells influenced by vitamin A. Combined with its ability to aid in the immune system, vitamin A may be valuable in preventing cancer. This is especially true for skin, lung, bladder and breast cancer. However, because it is a fat soluble vitamin, it is easier to reach toxicity levels. Unsupervised vitamin supplementation is not advised. Excess Vitamin A can lead to liver problems, fetal malformations and hip fractures. Foods that contain vitamin A yielding carotenoids, such as carrots and squash, are not toxic if consumed in large amounts. The body’s conversion of these carotenoids to vitamin A is slow and regulated. The skin may turn a yellow-orange but that’s okay! You’ll just look like you got a bad spray on tan. A good daily dose of vitamin A is between 700 to 900 micro grams.

Vitamin D is special because it is also considered a hormone. There is a cholesterol-like substance in our skin that is converted to pro hormone vitamin D when exposed to UVB rays. Our liver then takes the pro hormone and converts it to its active hormone form. This process will supply our body with 80% to 100% of our vitamin D needs. We should be exposing our hands, arms and faces to the sun at least two to three times a week for 5 to 10 minutes to optimize our body’s ability to do this. Vitamin D also helps regulate blood calcium levels, which makes sure that our cells are getting what they need when they need it. Another process in our body that needs vitamin D is bone metabolism. Vitamin D helps regulate the absorption and deposition of calcium in the bones. So it makes sense that a deficiency of this vitamin would lead to soft bones in adults and rickets in children. Rickets is a condition in which bones and teeth do not form properly. A good daily recommendation is 400-600 IU per day for those who are 51 or older and 200 IU per day for 50 and younger.

Sources: Baked Salmon, Sardines, Canned Tuna and Milk

Vitamin E

Vitamin E acts as a fat soluble anti-oxidant and protects from free radicals. Free radicals are highly reactive compounds that contain an unpaired electron. They roam around in the body looking for another electron to pair with. It is important to know that free radicals are a normal result of cell metabolism and immune system function. For example, a white blood cell will generate free radicals as a part of its action to stop an infection. So some exposure is okay. However, without vitamin E there to do its job, the free radicals pull electrons from other cell membranes. This alters the cell’s DNA, which can lead to cancer or damage the membrane in which the cell will die. Without enough vitamin E, cell membranes will break down.
It is recommended that 22-33 IU’s per day be a part of your daily diet. It is important not to exceed the recommended amount as too much vitamin E will interfere with vitamin K’s ability to form blood clots. Again, remember that vitamin E is a fat soluble vitamin and has a tendency to build up in your system.

Vitamin K’s biggest job is its role in blood clotting. Vitamin K also activates protein found in muscle, bone and kidneys, giving them a calcium binding ability. So it would make sense that a deficiency would lead to hip fractures. You should get between 90 to 120 micro grams of this vitamin each day.